I work in content personaliation engines. If one had control over your data and provide recommendations on what you watch, they can brainwash you to do whatever they want.

They can make you a porn addict. Or a Jehovah's witness.

They can make you take the side they choose in any topic.

They can manipulate you on who you vote.

Our own governments have been doing this for 50 plus years, but now Tick Tok allows the control to cross international boundaries.

By the Way, China doesn't allow their data to get out of China either